Maybe the most significant example of velocity and bullet shape influencing bullet terminal performance was with the revolutionary {for its time} change that occured in military bullets from the long heavy RN FMJ's to the pointed spitzers of the 1900-1910 era.

Hydrostatic affect and "explosive" wounds of the new bullets/loads are well documented in military literature, both on the battlefield and in test animals. Increasing velocity by around 500 fps or so dramatically changed the scene, along with the change in shape of the FMJ bullets. Bullet shape also infuenced this, in that spitzers upon striking flesh do not maintain direction consistently and yaw in the target caused catastrophic wounds that were not noted with the previous RNFMJ's. This is easily demonstrated in my test media, also. Previous heavy RN's were known as some of the least lethal military bullets ever made, unless impact occured at very close range where hydrostatic effect was magnified by high velocity. During the Boer War and Span-Amer War, wounds caused by the common highly stable RNFMJ bullets in excess of about 500+ or so yards were noted {with some implied surprise} by military medical personnel to be through and through without peripheral trauma {hoppdoc can give you the medical terminology}. Such wounds at similar ranges caused by the later spitzer FMJ's were noted as far more severe, as the ballistic properties of the bullets {higher initial velocity and pointed, more aerodynamic shape} allowed supersonic speeds to be carried out much further than that of the previous RNFMJ's.

Difference?

Velocity and bullet shape, obviously .

This example particularly demonstrates JPK's point of bullet shape and what can happen if bullet shape varies. All "FMJ's" are not created equal. Some military literature notes increase in kinetic energy as the deciding factor in increasing terminal performance of these bullets which could be said to be true as long as bullet shape is noted. But even merely increasing start speed will carry explosive wounding effect further afield even with the same bullets.

"Kinetic Energy" is not a perfect formula by any means, but it cannot be said to be "wrong" in every case. And, depending on the "case", it can be a very poor predictor of comparative "killing power".